EVEN the time to breathe a sigh of relief for the summer respite granted by Covid that a new viral threat is appearing on the horizon: for some weeks the cases of dengue, also known as “bone-breaking fever” for the intense pains, have multiplied in Singapore bone and muscle that it can cause when it is symptomatic. As of June 1, the Asian city-state had already exceeded 11,000 cases – more than double the number reported in 2021 – and registered the first victim, inaugurating the season of this disease, which has now become endemic in the region, well in advance. The epidemic was fueled by an unusual and prolonged heat and by frequent thunderstorms that favored the activity of mosquitoes that transmit the virus.
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Europe is also at risk due to rising temperatures
If the Singaporean emergency immediately worries the other countries of Southeast Asia, it does not leave even Europe indifferent: year after year, climate change expands the habitat of tropical mosquitoes while the globalization of trade and travel multiply the possibilities of transmission to long range. In our country the possibility of getting sick is low but not so remote: every year in our country there are dozens of cases among people returning from exotic destinations. True outbreaks, however, are infrequent.
What is dengue
Endemic to tropical regions, dengue is an infectious disease caused by four variants of the same virus, called serotypes, and is transmitted indirectly by mosquitoes which, in turn, have bitten an infected person. The main vector is the yellow fever mosquito (Aedes aegypti), typical of tropical regions but can also be transmitted by the tiger mosquito (Aedes albopictus). Within 5-6 days of the sting, the disease can progress asymptomatically or manifest itself with very high fever accompanied by acute headaches, pains around and behind the eyes, severe pain in muscles and joints, nausea and vomiting, irritation of the skin that can appear on most of the body, with a mortality rate that can exceed 20%.
There is no cure, mortality rate over 20%
To date, we do not have a specific cure. However, there is a vaccine, Dengvaxia, approved in about twenty countries, but according to the World Health Organization “it has proved effective only in those who have already had a previous infection with the virus, while it involves an increased risk of serious illness in those who have their first natural infection after vaccination “. Characteristic that pushes WHO to recommend it “are in patients with previous dengue, following an antibody test, as an integrated prevention strategy”.
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The situation in Singapore
According to the WHO, cases of dengue have increased 30 times over the past 50 years. Before the pandemic restricted the movement of people, 5.2 million cases were recorded worldwide in 2019. Epidemics across Asia have claimed thousands of lives, bringing health systems to their knees in countries like the Philippines and Bangladesh. The worst dengue outbreak in Singapore’s history occurred the following year causing 35,315 cases and 28 deaths. “As of May 28, 2022, about 11,670 cases of dengue have been reported, 10% of which required hospitalization,” a spokesperson for the Singapore Ministry of Health told CNN. According to the same source, admissions to emergency wards fortunately remain at “a manageable level”. However, since it is a disease that respects a precise seasonality, the risk that in the coming weeks the cases will multiply further is concrete since we are still far from the usual epidemic peak.
The golden year of dengue
The golden year of dengue is the result of at least two factors: the emergence of a new dominant viral strain but above all the exceptional hot and humid weather of the past few weeks. Singapore’s Weather Service says the country is warming up twice as fast as the rest of the world. Daily maximum temperatures could reach 37 ° C by the end of the century. According to experts, the combined action of heat and increasingly unpredictable torrential monsoons can only worsen the dengue problem in Singapore.
Dengue in Italy
“The island of Madeira and a small area on the Black Sea coast are the only regions in Europe where the mosquito Aedes aegypti, the main vector of dengue, is endemic. In the rest of the continent, for now, the disease is transmitted, in a less effective way, by the tiger mosquito, giving rise to outbreaks fed by people who have returned home after they have been infected in countries where the disease circulates “, the infectious specialist said. Federico Gobbitravel medicine expert of the IRCCS Sacro Cuore-Don Calabria Hospital in Negrar, confirming that “climate change causes the expansion of the geographical areas suitable for hosting Aedes aegypti: to date, this mosquito is unable to survive our winter but with a warmer climate it could settle permanently in Italy too “.
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Asymptomatic in most cases
As with other exotic mosquito-borne diseases – such as chikungunya, West Nile fever or zika – our country has an imported case surveillance system that is ready to go off at the first alert. If anything, the problem with limiting dengue is that in most cases the disease is asymptomatic. The first infection, in fact, rarely leads to complications. However, subsequent infection with a different serotype of the virus can trigger immune reactions that lead to bleeding. “Nevertheless, when you return from a country at risk, it is advisable to pay attention to any symptoms, even mild ones, and go promptly to specialized centers. In case of confirmation, the intervention protocol is triggered which provides, for example, the reclamation of green areas surrounding the house to eliminate tiger mosquitoes “continues Gobbi. Awareness of the risks on the part of citizens represents a sine qua non for stemming the spread of the disease and also passes through consultancy in travel medicine clinics. Before taking the plane it is always better to know what you are going to encounter. And above all, what could be brought home.
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